Current open procedures for tissue ablation (e.g., tumor destruction and/or removal) are disruptive and cause considerable damage to healthy tissue. In tumor treatments, a physician must exercise care during a surgical procedure to avoid cutting the tumor in a manner that creates seeding of tumor cells, resulting in metastasis. Also, some patients are not eligible for open surgical techniques due to their general state of health. In recent years, products have been developed to minimize the traumatic nature of traditional surgical procedures; however, ablation surgery is by no means a trivial procedure.
Chemotherapy and radiation therapy are alternatives to open surgical procedures for treating tumors, but they expose healthy tissues and sometimes the entire body to toxic chemicals. Side effects from chemotherapy and radiation therapy are well known and include hair loss, loss of appetite, and malaise. Moreover, such chemical treatments often fail to achieve complete destruction of tumors at doses acceptable to the patient, ultimately leading to recurrence and the need to repeat the procedure.
An alternative to conventional surgical techniques and chemical treatment is the use of hyperthermia for tissue destruction and/or removal through necrosis. Treatment methods for applying tissue-damaging heat to target tissues such as tumors include the use of direct contact radio-frequency (RF) applicators, inductively coupled RF fields, microwave radiation, and a variety of simple thermal conduction techniques. These techniques are often referred to collectively as thermal ablation techniques.